High voltage switching device



July 21, 1936. R. R. PITTMAN ET AL HIGH VOLTAGE SWITCHING DEVICE FiledJan. 11, 1935 2 Sheets-Sheet l CONDUCTING MATERIAL 60 N DUCTING MATERIALATTORNEY July 21, 1936. R. R. PITTMAN ET AL HIGH VOLTAGE SWITCHINGDEVICE 2 Sheets-Sheet 2 Filed Jan. 11, 1935 0 4 Q a 'mm HEW? "WE:

INVENTO ATTORNEY Patented July 21, 1936 UNITED STATES PATENT OFFICE HIGHVOLTAGE SWITCHING DEVICE Ralph E. Pittman and Carroll H. Walsh, PineBluff, Ark.

This invention relates generally to switching equipment for use inconnection with electric circuits, and particularly to high tensionswitching devices. I

It is now well known that high voltage airbreak switches which dependfor their interrupting ability upon the elongation of thecircuit-interrupting arc in the open air are ineffectivecircuit-interrupting devices, due to the fact that only a fractionalpart of the circuit voltage may be required to sustain the arc undersuch conditions. It is also well known that the arcs resulting from theopening of such switches may be long compared to economical clearancesbetween live parts, and live parts and ground, and that the operation ofthese switches under certain conditions constitutes a hazard both to theoperator and to the connected equipment.

It is an object of the present invention to provide means fortransferring an open-air circuitinterrupting arc to a restricted spacewithin a tubular insulator, to the end that the voltage required tosustain the arc therein is many times that required for an are playingin the open air.

.26 A further object is to provide means responsive to an openingmovement of an air-break switch for reducing the dielectric strength ofan associated tubular insulator, so that the length of are required toefiect the abovementioned transfer is greatly reduced. I I

A further object is the provision of. a switching device embodying anarc suppressor in combination with a main current carrying switch, inwhich the arc suppressor changes in effect from 35 a conductor to aninsulator in response to the passage of current therethrough.

Afurther object is the provision of means responsive to a predeterminedopening movement of a i switch for interposing an arc suppressor in 40series relation with the contacts of the switch.

Another object is the provision of an arc suppressor having externallyoperable means for changing the conductivity of a path internallytherethrough.

' An additional object'is the provision of a simple and effective aresuppressor or arc extinguishing device especially applicable forcombining with high tension air-break switches in order to effect anincrease in their interrupting capacity.

50 with the above and other objects in view which will appear as thedescription proceeds, our invention resides in the novel combination andarrangement of an arc suppressor with a switch to the end that a numberof. the parts making up 55 th resulting switching device perform aplurality of essential and desirable functions, and in the novelfeatures of construction of the arc suppressor itself.

In the description of the embodiment of the invention here presented,specific language will 5 be used for the purpose of facilitating anunderstanding of its construction and operation, but it will beunderstood that various changes in the specific construction may be madewithout departing from the principles of. the invention. 10

In the drawings (2 sheets) Fig. 1 is an elevational view of the arcsuppressor employed in the device, shown in section along the planeindicated by the line II in Fig. 3.

Fig. 2 is a side elevational view of the arc sup- 15 pressor.

Fig. 3 is a plan view of the arc suppressor, viewed from above.

Fig. 4 is a plan view of the switching device, viewed from above. 20

Fig. 5 is a side elevational view of the switching device.

Fig. 6 is a sectional view of the device taken along the plane indicatedby the line II in Fig.

3, illustrating the device with the valve open.

Fig. 7 is a sectional view of the lower electrode vent, taken along theplane indicated by the line VII-VII in Fig. 2.

Referring now in detail to the illustrations of the arc suppressor asshown in Figs. 1, 2, and 3, a hollow conducting electrode H is securedto the lower end of a tube of insulating material ill by means of.cooperating threads on the respective members. A desirable material forthe tube I0 is hard fiber. For conveniently supporting the tube ill in avertical position, the electrode II is provided with an integraloutwardly extending flange adapted to be secured to a flat surface, andin addition is provided with a downwardly and outwardly extendingtube-like end portion for directing the discharge from the tube l0 awayfrom contiguous live parts.

Adjacent the upper end of the tube I0 is secured, by means ofcooperating threads, the hollow upper conducting electrode I2. Both theelectrodes I l and I! are provided with tube-like portions extendingtoward each other over the external surface of the tube ID for thepurpose of increasing the bursting force required to rupture the tube.

The upper electrode I2 is provided with. an upwardly and outwardlyextending integral wall to provide a container for a quantity of finelydivided conducting material 30, such as aluminum powder, and an enlargedrecess it between the upper portion forming the container and the lowerportion adjacent the tube I0. A metal cover is secured to the top of theelectrode [2, in any suitable manner, as by the screws 25.

Into the upper end of the recess 13 is fitted the valve 14, the latterbeing screwed into the lower end of the metal tube 15. Adjacent theupper end of the metal tube is secured the metal housing 22 by the nuts2|, which are adapted to screw on the outside of the tube 15, and clampthe housing 2| rigidly between them. A spring 23 is interposed betweenthe housing 22 and the cover 24, and the latter is provided with anopening through which the tube l5 may reciprocate. In this manner thespring 23 normally maintains the valve 14 in close engagement with thevalve seat at the upper end of the recess l3. The cap is arranged to bescrewed on the outside of the tube l5, so that it may be removed for thepurpose of pouring the finely divided conducting material therein. Aplug l8 within the tube l5 diverts the conducting powder through theopenings H in the wall of the tube so that it may be deposited in thespace surrounding the tube. A definite amount of the conducting material30 flows back into the tube below the plug l8 through the openings [9 inthe wall of the tube.

The housing 22, as shown in Fig. 2, is provided with downwardly andinwardly extending strap portions having their ends bent inwardly normalto the axis of the tube ID for the purpose of cooperating with the yokemember 48, the latter being pivotally mounted on an outwardly extendingportion of the electrode l2 by means of the pivot 28.

From this description it will be seen that an upward movement of theoutwardly extending portion 29 of the yoke member 48 will cause adownward movement of the housing 22 against the bias of the spring 23.Since the tube l5 and the valve 14 are rigidly secured to the housing22, such a movement causes the valve. i4 to move away from its seat, andpermits the powdered supports in the usual way the insulators 33, 34,

and 35, on the tops of which is mounted the live parts of a switch. Thecontrol rod 32 is rigidly secured to the insulator 33, and in responseto a rotary movement of the former, motion is transmitted to the blade39 through the movement of the crank 36, the connecting rod 31, and thebent member 38, causing the movable contact member 40 to move upwardlyaway from its cooperating contact member H.

The arc suppressor, designated in its entirety by the numeral 3|, issupported adjacent the top of the insulator by means of the bolts 46extending through both the outwardly extending flange of the electrode Hand the flat member -45, the latter being rigidly secured to the top ofthe insulator 35.

The line terminals 42 and 43 provide in the usual way a means forconnecting respectively .a load anda line conductor to the, switch.

Assuming that the switching device is connected in series relation witha conductor carrying current, the control rod 32 may be rotated in anysuitable manner, causing an upward movement of the contact member awayfrom its cooperating contact member 4|, as before described. An initialarc is thus established between the members 40 and 4|, which continuesthrough the opening movement of the switch until the member 40 engagesand urges upwardly the outwardly extending portion of the yoke member29, at which time a measured amount of conducting powder is dischargedinto the tube l0, as previously described. The relative position of theelements constituting the arc suppressor at this time are illustrated byFig. 6. The conducting material coats the interior of the tube Ill andthereby lowers its electrical strength so that the voltage of arebetween the contact members 40 and M is sufficient to break down a pathinside of the tube [0 between the electrodes H and I2. In this mannerthe circuit-interrupting arc is transferred to the inside of the tubeIll, where it is extinguished by the well known expulsion action.

The member 29 is arranged to move out of the path of the contact member40 so that the latter passes the former in sliding engagement followingthe actuation of the valve l4. -The arcing horn 26,-which iselectrically in contact with the "portions of the downwardly extendingstraps -41 of the housing 22 and the container-portionoi theupperelectrode I2 to permit the member-'29 to move in a clockwisedirection about the pivot 28 sufliciently to permit the contact member40 to pass the member 29 in response-toa closing'movement of the switch,as shown by the broken lines in Fig. 1. The arrangement is thereforesuch that the valve mechanism is caused to deliver conducting materialto the tube In only in response to an opening movement of the switchingdevice.

The purpose of this arrangement is to assure a fresh coating ofconducting powder on the interior of the tube in response to eachopening movement of the switching device. In the absence of such anarrangement, vibration by winds or other causes may cause considerableportions of the interior coating to be lost from the inner surface ofthe tube l0 after the elapse of a period of time, and thus prevent theproper operation of the device.

,It .will be seen from the above description that our device depends forits operation upon the reduction of resistance of an insulating memberbridged across the terminals -of a circuit-interrupting arc resultingfrom the opening of the switch, in order to transfer the arc to theinsulating member, and upon the resulting action of the are upon themember to the end that the voltage required to sustain the arc in itsnew 0 location is greater than the voltage available across theterminals of the :device.

We claim as our invention:

1. The combination with a main current car suppressing device includinga hollow tube of insulating material, movable means for actuating saidmain current carrying switch, and means responsive to a movement of saidmovable means in a direction to open said main current carrying switchfor depositing a coating of finely divided conducting material on theinternal surface of said hollow tube, said movement interposing saidhollow tube between said separable contacts of said main currentcarrying switch.

2. The combination with a main current carrying switch of an arcsuppressor including a hollow tube of insulating material, movable meansfor actuating said switch, and means responsive to a movement of saidmovable means for depositing a coating of finely divided conductingmaterial on the internal surface of said hollow tube.

3. A switching device comprising a main current carrying switch and anarc suppressor associated with said switch, said arc suppressorincluding a hollow tube of insulating material, movable means foropening and closing said switch, and means responsive only to a movementof said movable means in a direction to open said switch for depositinga coating of finely divided conducting material on the intemal surfaceof said hollow tube.

4. An arc suppressor comprising a hollow tube of insulating material, achamber mounted on the upper end of said tube, a quantity of finelydivided conducting material within said chamber, valve means normallypreventing the passage of said conducting material from said chamber tosaid tube interposed therebetween, and means external of said suppressorfor actuating said valve means.

5. An arc suppressor comprising a hollow tube of insulating material, achamber mounted on the upper end of said tube, a quantity of powderedconducting material within said chamber, valve means interposed betweensaid chamber conducting material from said chamber to the interior ofsaid tube, externally positioned valve actuating means associated withsaid valve, and means responsive to a movement of said valve actuatingmeans for releasing a measured quantity of said conducting material intosaid tube.

6. A switching device comprising a main current carrying switch having amovable contact member, an arc suppressor associated with said switch,said are suppressor comprising a hollow tube of insulating material, ahollow chamber mounted on the upper end of said tube, a quantity ofconducting material within said chamber, valve means interposed betweensaid chamber and the interior of said tube, resilient means normallymaintaining said valve means in closed position for preventing thepassage of said conducting material from said chamber to the interior ofsaid tube, and valve actuating means positioned in the path of movementof said movable member, whereby a quantity of said conducting materialis deposited in said tube in response to a movement of said movablecontact member.

7. An are suppressor comprising a hollow tube of insulating material, achamber mounted on the upper end of said tube, a quantity of finelydivided conducting material within said chamber, valve means normallypreventing the passage of said conducting material from said chamber tosaid tube interposed therebetween, externally positioned valve actuatingmeans associated with said valve means, and means responsive to amovement of said valve actuating means for releasing a measured quantityof said conducting material into said tube.

RALPH R. PIT'I'MAN. CARROLL H. WALSH.

